Abstract: In MDE, large models must be collaboratively
developed in teams. Collaboration is usually supported by
optimistic versioning based on workspaces and a
repository. Workspace copies of a model are synchronized
with the repository version by an update function. Most
update functions currently available compromise the
consistency of a model. We present a new approach which
guarantees updated models to be consistent and processable
by standard visual editors without post-processing. Our
approach assumes changes in the repository to be
represented as a consistency-preserving edit script. This
edit script is executed in a controlled, interactive
manner on the workspace copy. Unlike 3-way merging, our
approach needs no conflict analysis. Conflicts are
detected and resolved interactively. Our approach offers
improved usability and requires less implementation effort
than existing approaches.